The instant invention relates to stacking of papers, and more particularly to stacking different length papers using a fold-down perforated ramp to levitate documents and limit bounceback.
Papers exiting a roller nip on a ramp so that they can be stacked against a registration edge in the feed direction will tend to drop down and slide along the preceding papers, thereby causing three problems. The first problem is that static charges on the paper and friction prevent the papers from arriving at the proper location. The second problem is a complication due to handling two different length papers without requiring operator intervention so that, for example, 11 inch papers can travel the additional three inches required by 14 inch long papers. The third problem is that, when dealing with at least two different paper lengths, system to limit bounceback of the paper sheets is required in order that the papers be stacked in proper registration.
Air introduced through a narrow slot located directly below the document exit slot can provide a stream of air which levitates the paper sheets and avoids the frictional contact described previously. The momentum derived from the exit roller nip allows the paper sheet to proceed to the stack registration location unhampered by the contact friction avoided by the aforesaid airstream. In order that the levitating benefits of air introduced below the paper sheets be realized, the ramp must be perforated. Since different lengths of paper are to be accommodated, the perforated ramp must be retractable. However, when space is limited, this cannot be accomplished.
Accordingly, the instant invention overcomes the foregoing problems by providing a levitating, segmented ramp which can accommodate automatically, for example, the stacking of an 11 inch document in its raised position at the same leading edge location that the stored position of the ramp can accommodate 14 inch documents.